mojodragon

I'm 29 years old, 6'2" tall, and weigh 150 lbs. A month ago, I started training for my first marathon, and have been running more than I have in my whole life. In that month, I've lost 20 lbs, and my wife tells me that I'm doing something wrong. I think she may be right. She says that I'm not eating enough to support my running habit, and that I'm losing muscle mass. Has anyone ever been through this, and what did you do to correct the situation? I've noticed that I'm craving carbs, and that after a long run, I don't really feel much like eating. What say you?